1. Field of the Invention
The present invention relates to tabletized ionene polymers, methods for their preparation, and their use in water treatment.
2. Description of Related Art
Biological fouling is a persistent nuisance or problem in all varieties of aqueous systems. Biological fouling can have a direct adverse economic impact when it occurs in industrial process waters, for example in cooling waters, metal working fluids, or other recirculating water systems such as those used in papermaking or textile manufacture. If not controlled, biological fouling of industrial process waters can interfere with process operations, lowering process efficiency, wasting energy, plugging the water-handling system, and even degrading product quality.
Biological fouling of recreational water systems such as pools, spas, or decorative (or ornamental) water systems, (e.g., ponds or fountains), can severely detract from people's enjoyment of them. Biological fouling often results in objectional odors. More importantly, particularly in recreational waters, biological fouling can degrade the water quality to such an extent that it becomes unfit for use and may even pose a health risk.
Sanitation waters, like industrial process waters and recreational waters, are also vulnerable to biological fouling and its associated problems. Sanitation waters include, for example, toilet water, cistern water, and sewage treatment waters. Due to the nature of the waste contained in sanitation waters, these water systems are particularly susceptible to biological fouling.
Ionene polymers have often been used to control or prevent biological fouling, including biofilm and slime formation, in aqueous systems. Advantageously, ionene polymers, or polymeric quaternary ammonium compounds (polyquats), generally do not foam excessively in water or aqueous systems, do not irritate skin, and exhibit extremely low toxicity to warm-blooded animals. These characteristics along with their ability to control or prevent biological fouling cause ionene polymers to be excellent choices for water treatment.
Ionene polymers are commonly sold and used as liquid compositions such as aqueous solutions or formulations. Solid forms, including tablets, of ionene polymers have been disclosed in U.S. Pat. Nos. 5,142,002 and 5,419,897. Other water treatment chemicals are often sold in solid forms, such as tablets or pucks. The following patents describe various solid forms of water treatment chemicals for use in a number of different aqueous systems: U.S. Pat. Nos. 4,310,434, 4,396,522, 4,477,363, 4,654,341, 4,683,072, 4,820,449, 4,876,003, 4,911,858, 4,961,872, and 5,205,955 as well as U.K. Patent No. 1,601,123, PCT Application WO 91/18510, PCT Application WO 92/13528, and European patent Application No. 0 525 437 A1.
In some applications solid forms provide advantages over liquid compositions. Well formulated solid forms provide increased stability and reduce exposure to chemicals, solvents, or vapors. In a solid, different ingredients may be successfully combined where such a combination in a liquid might lead to unwanted reactions and potential loss of activity. Using a solid form, a chemical composition can often be packaged and shipped in a more concentrated form than with liquid compositions. Solid forms can also reduce or eliminate concerns regarding the liquid spilling or containers breaking during shipping or handling.
At the point of use, solid forms may also offer additional advantages over liquid formulations. Solid forms provide unit dosing and a uniform delivery system reducing errors in amounts used. Solid forms of water treatment chemicals can also be formulated to provide sustained or prolonged release of chemical to the aqueous system.
As shown by the above discussion, it would be desirable to combine the biological efficacy of an ionene polymer with the advantages of a solid formulation. Solid forms of ionene polymers would compliment the utility of liquid ionene polymer formulations. Accordingly, there exists a need for solid form of an ionene polymer useable in water treatment and other uses.